Well
I didn't know about this sinister matter until Xarob pointed it
out. I was just explaining about how it was best to sign up to
the bargain-price ISP (£9.99/month
24 hour availability) V21 unmetered access by means
of the affiliate page www.zyra.org.uk/v21.htm ,
pronounced "W W W dot ZYRA dot ORG dot UK forward-slash V21 dot
HTM" and I was informed that in fact FORWARD-SLASH is an
affectation, all too common in the same way a lot of people say
things like "PIN number" and "AC current" and
Fine ToothComb and
greengrocers are notorious for using an inadvertent possessive apostrophe in fruit-and-veg
related plurals such as the classic mistake: "banana's".
So, here's the correct version:

There
is an ascii character known as SLASH and which looks like this: /

There
is another ascii character
which is an oddity known as the BACKSLASH and which looks like
this: \

The
SLASH is the symbol of DIVIDE in computer programming and is used
for directories in proper operating systems such as UNIX (also
see Linux). However,
apparently when Microsoft bodged up
one of their early operating systems (even before the travesty
known as "Microsoft Windows") they ended up having to
use BACKSLASH (\) for directories because they'd made the mistake
of using SLASH (/) for the OPTIONS (a situation which had already
been solved in early Unix by doing it properly). As a result,
Microsoft has always had a vested interest in creating confusion
about the nature of SLASH and its quirky mirror-image BACKSLASH!
To try to cover the embarrassment they supposedly invented the
term "FORWARD-SLASH" to give some kind of pretend
credibility upon the idea that there was some kind of sense to
slashes in directories being back-to-front somehow. There was
even one point where there was a rumour that the terminology for
these was the other way around and that the proper slash was
"\" and that the other one was "backslash".
This kind of misdirection all helped to cause more confusion,
thus achieving various sinister disempowering aims upon the
populace and possibly making more money for Microsoft by wasted
technical-support resources.

In
the end, people weren't quite as microsoftinthehead as they were
thought to be and proved too clever to be fooled by the idea that
left and right were the other way around, but the term FORWARD-SLASH
got stuck and adopted, even by people who should know better,
such as The BBC!

So,
to get it right, when saying www. ... etc / something, it's
"SLASH", and not "FORWARD-SLASH".

Better
still, it would be nice if, instead, the whole "slash"
business was dropped in favour of a brilliant idea suggested by
the Grand Master DJ John Peel, who declared that "slash"
was unnecessarily violent-sounding, and that instead we should
say "STROKE". For example, www.bbc.co.uk/radio1 pronounced
"W W W dot BBC dot CO dot UK STROKE Radio One".
I think that's much better!

Matt adds: "If I may...
Mr Peel was not the originator of the usage of 'Stroke' to
describe the slash character when verbally quoting URLs. It was
started by Mr Stephen Fry - and as such, it is an obvious 'Fry-ism'
".